本文關(guān)鍵詞： 煤液化 液控閥 空蝕機理 數(shù)值模擬 空蝕預(yù)測　出處：《浙江理工大學(xué)》2011年碩士論文　論文類型：學(xué)位論文

【摘要】：煤液化高溫液控閥具有進出口壓降大、介質(zhì)流速高、操作頻繁和運行工況多變等特點,其空蝕損傷十分嚴重。現(xiàn)有的科研攻關(guān)主要集中在通過材質(zhì)升級和表面強化等手段提高閥體的抗空蝕性能,卻收效甚微,至今德國SchuF閥的使用壽命不足1個月。本文在空蝕機理研究的基礎(chǔ)上,針對液控閥的實際運行工況、流體物性和結(jié)構(gòu)參數(shù),開展空化流動的數(shù)理建模和數(shù)值分析,完成了空蝕失效的定量預(yù)測,為液控閥的結(jié)構(gòu)和操作優(yōu)化提供參考。 本文從空蝕機理出發(fā),基于空蝕損傷的力學(xué)作用機制,構(gòu)建了近壁面單空泡變形和潰滅的數(shù)理模型,計算得到了空泡變形過程中泡壁的運動規(guī)律及其潰滅過程中產(chǎn)生的高速微射流和沖擊壓力;在此基礎(chǔ)上,完成了在近壁面、附壁面、無限遠場和成對空泡等環(huán)境特征下空泡潰滅過程的數(shù)值計算,并重點分析了在近壁面狀態(tài)下空泡至固壁距離、空泡內(nèi)外壓力差、表面張力系數(shù)、液體粘性和來流等因素對空泡潰滅過程的影響;在空蝕機理研究的基礎(chǔ)上,以煤液化熱高分液控閥為研究對象,構(gòu)建了空化流動的計算模型;運用Aspen軟件,計算流體的物性參數(shù),運用Fluent軟件,獲得兩種典型結(jié)構(gòu)的液控閥內(nèi)部的流速、壓力和氣相分率等關(guān)鍵流體動力學(xué)參數(shù)的分布規(guī)律,完成了液控閥空蝕失效區(qū)域的定量計算,并結(jié)合液控閥的典型失效案例,驗證了數(shù)值模擬方法的可靠性。同時,對比分析了進出口壓力、操作溫度、閥口開度、固體顆粒、閥芯角度等參數(shù)對空化區(qū)域和強度的影響,完成了液控閥的空蝕失效預(yù)測。本文的研究方法還可推廣應(yīng)用于煤液化裝置其它設(shè)備、管道、泵閥的空蝕失效預(yù)測、結(jié)構(gòu)優(yōu)化設(shè)計、風(fēng)險評估和壽命預(yù)測等,為煤液化裝置的設(shè)計選材和安全運行提供技術(shù)支持。 本論文創(chuàng)新性研究在于:1)數(shù)值分析了空泡在不同環(huán)境下的潰滅特性,捕捉到空泡在各潰滅瞬間的形態(tài)特征,完成了空蝕力學(xué)作用機制的定量計算,并對空泡潰滅的各影響因素進行定量分析;2)同時分析空泡內(nèi)外壓力差和液體流動對空泡潰滅的影響,并完成了雙空泡潰滅特性的初步研究;3)采用煤液化熱高分液控閥的實際操作參數(shù)和流體物性,完成了液控閥的空蝕失效預(yù)測,使計算結(jié)果更加接近工程實際。同時,考慮了固體顆粒相與空化流場間的相互作用,分析了顆粒的存在對空化流場的影響。?
[Abstract]:Coal liquefaction of high temperature liquid control valve with pressure drop, high flow rate of medium, frequent operation and various operating conditions and other characteristics, the cavitation damage is very serious. The current research focuses on improving the performance of anti cavitation valve by upgrading the material and surface strengthening method, but have little effect, since the German SchuF valve life is less than 1 months. Based on the study of the cavitation mechanism, according to the actual operation condition of hydraulic control valves, fluid properties and structural parameters, carry out mathematical modeling and numerical analysis of cavitation flow, completed the quantitative prediction of cavitation failure, provide a reference control structure and operation optimization of the valve for liquid.
This article from the mechanism of cavitation, mechanical mechanism of cavitation damage based on building the mathematical model of single bubble deformation and collapse near the wall, to calculate the deformation of bubble movement and its collapse of bubble wall in the process of high speed micro jet and impinging pressure; on this basis, completed in the past the wall of the wall, numerical calculation of infinite bubble collapse process of the far field and the environment of another bubble, and analyzed in the near wall to wall distance under the condition of cavitation, cavitation and pressure difference, surface tension coefficient, the influence of liquid viscosity and flow on bubble collapse in the process; based on the cavitation mechanism, coal liquefaction heat high hydraulic control valve as the research object, constructs the calculation model of cavitating flow; using the Aspen software, the calculation of physical parameters of fluid, the use of Fluent software, obtained two kinds of typical structure of hydraulic control The valve internal flow, pressure distribution and key hydrodynamic parameters rate, the hydraulic control valve cavitation failure area of quantitative calculation, combined with the typical hydraulic control valve failure case, verify the reliability of the numerical simulation. At the same time, comparative analysis of the import and export pressure, operating temperature, valve port the opening degree of solid particles, effect of valve angle on cavitation area and intensity, completed the cavitation liquid control valve failure prediction. The method can also be applied to other coal liquefaction unit equipment, pipeline, valve cavitation erosion failure prediction, structural optimization design, risk assessment and life prediction. Provide technical support for the design of material and safe operation of coal liquefaction device.
The main innovation in this paper lies in: 1) the numerical analysis of the characteristics of bubble collapse in different environments, to capture the bubble morphology in the collapse of the moment, to complete the quantitative cavitation mechanical mechanism is calculated, and the factors affecting the bubble collapse by quantitative analysis; 2) and analysis of the influence of cavitation pressure difference between the inside and outside and the liquid flow on the bubble collapse, and completed the preliminary study on the characteristics of double bubble collapse; 3) the actual operating parameters and fluid properties by coal liquefaction hot high pressure hydraulic control valve, the hydraulic control valve cavitation failure prediction, the calculation results are more close to the actual project. At the same time, the interaction of solid particles and the cavitation flow considering Inter, analyzed the influence of the presence of the particles of cavitation flow.?

【學(xué)位授予單位】：浙江理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2011
【分類號】：TH137.52

【引證文獻】

相關(guān)期刊論文 前1條

1 偶國富;周永芳;鄭智劍;章利特;吳崇芳;;空蝕機理的研究綜述[J];液壓與氣動;2012年04期

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本文編號：1463902